Device for attenuating sound waves and the combination thereof with a curb and ventilator



3,330,3 79 OMBINATION TOR L` COOK July 1l, 1967 DEVICE FOR ATTENUATING SOUND WAVES AND THE C THEREOF WITH A CURB AND VENTILA Filed NOV. l2, 1964 2 Sheets-Sheet l 9 52 25 Z6 Z7 /9 INVENTOR A TORNEY July l1, 1967 L. COOK 3,330,379

DEVICE FOR ATTENUATING SOUND WAVES AND THE COMBINATION THEREOF WITH A CURB AND VENTILATOR Filed Nov. l2, 1964 2 Sheets-Sheet 2 llll Il INVE TOR ATTORNEY 3,3%;379 Patented July 1l, 1967 DEVICE FOR ATTENUATING SOUND WAVES AND THE COMBINATION THEREOF WITH A CURB AND VENTILATOR Loren Cook, Berea, Ohio, assigner to Loren Cook Company, a corporation of Ohio Filed Nov. 12, 1964, Ser. No. 410,522 16 Ciaims. (Cl. ISI-50) My invention relates to a device having a passage therethrough and acoustical material associated therewith for attenuating sound waves. It also relates to the combination of a curb and a device for attenuating sound waves, and to the combination of a curb, a device for attenuating sound waves, and a ventilator in which the curb surrounds an opening in a room or building and the device for attenuating sound waves has its lower end portion supported by the curb and its upper end portion shaped to support the ventilator.

In certain buildings, such as hospitals, libraries, churches, and auditoriums, in which extraneous noise is particularly objectionable, it is desirable to attenuate sound waves passing through the usual ventilator which are initiated from noises arising outside of the building and particularly those noises which are initiated by the motor and the fan or blower when power-operated means is energized to expel contaminated air from a room or building.

In my copending application, Ser. No. 310,818 filed September 23, 1963, now abandoned, a curb is provided having side walls containing acoustical insulating material and in accordance with the present invention, my improved device for attenuating sound waves may be utilized in combination with a ventilator and such a curb or when a less expensive structure is desired, it may be used in combination with a ventilator and a curb of the usual built-up type.

It is therefore an object of my invention to provide a device having a passage therethrough and acoustical insulating material associated therewith for attenuating sound waves passing through the device.

Another object of my invention is to provide an improved combination including a curb and a device in the form of duct means having acoustical insulating material associated therewith for attenuating sound waves passing through the device and the curb and especially sound waves initiated by power-operated means arranged in a ventilator supported on the sound attenuating device for drawing contaminated air outwardly from a room or building.

A further object of my invention is to provide in combination a curb including side Walls having acoustical insulating material associated therewith, a sound attenuating device containing acoustical insulating material and having its lower portion supported upon the curb, and a ventilator support upon the upper portion of the sound attenuating device.

My invention will be better understood by reference to the accompanying drawings in which:

FIG. 1 is a cross sectional view of my improved device showing it mounted on a curb having side walls containing an acoustical insulating material, and a ventilator mounted upon the device which is shown partly in elevation and partly in section;

FIG. 2 is a cross sectional view taken on a plane passing through the line 2-2 of FIG. 1 with the roofing material omitted;

FIG. 3 is a plan view of my improved device taken on a plane passing -through the line 3 3 of FIG.. 1;

i FIG. 4 is a side elevational View of my improved device;

FIG. 5 is a side elevational View of a modilication of my improved device with parts broken away to show underlying structure and parts in section; and

FIG. 6 is a sectional view showing my improved device mounted upon a commercial curb of the usual builtup type and having a ventilator mounted thereon, only a fragmentary portion of which is shown but which may be similar to that shown in FIG. 1.

As illustrated in the accompanying drawings, my improved device for attenuating sound waves as shown in FIGS. 3, 4 and 5 is arranged between a curb 2 or 2a and a ventilator 3 in FIGS. 1, 2 and 6 in which it is designated generally by the numeral 1. As shown, it consists of outer side walls 4 formed of a suitable metal, such as aluminum, three of which walls if desired may be formed from a single sheet. Each of the side walls has an inwardly extending upper flange 5 and a lower tlange 6 inclined outwardly to enable the device to be easily assembled on a curb.

The side walls also consist of a first pair of oppositely disposed perforated inner walls 7 and a second pair of oppositely disposed perforated inner walls 8 which inner walls are arranged opposite to and spaced from the respective outer walls and the upper portion of each of which has an outwardly extending flange 9, the outer edge portion of which is arranged below land is welded or otherwise secured to the inwardly extending ange on the outer wall opposite thereto. Each of the inner walls also has an outwardly extending lower flange 10 which is welded or otherwise secured to the lower portion of the outer side wall 4 arranged opposite thereto. Prior to assembly, however, the spaces between the outer walls 4 and the inner walls 7 and 8 are filled with an acoustical insulating material, such as felt or breglass, designated generally by the numeral 11.

To assist in attenuating sound waves passing through the device, each of the inner side walls 7 consist of upper and lower V-shaped projections 12 and 13 separated by a vertically extending wall 14. The other pair of inner walls S, however, extend vertically and form supports for a perforated tube 15 or a plurality of perforated tubes 15 and 15a. The opposite ends of tube 15 or the opposite ends of each of the tubes 15 and 15a are welded or otherwise secured to the inner side walls 8. Before being secured to the inner side walls 8, however, the tube 15 as shown in FIG. 4 or tubes 15 and 15a as shown in FIG. 5 are filled with an acoustical insulating material, such as felt or fibreglass, and a metal plate 16 which may be formed of aluminum is arranged within tube 15 or -a metal plate 16 may be arranged within each of the tubes 15 and 15a to vary the density of the sound insulating material and to prevent it from settling to the bottom of the tube or tubes. It also acts to reect and further attenuate the sound waves. 'Ihe number of tubes provided will of course depend upon their size and the size of the ventilator. Usually one tube will be suf'rlcient but if the ventilator is comparatively large, two or more tubes may be provided.

The particular curb and ventilator shown in FIGS. 1 and 2 are well known commercial products and while I do not desire to limit myself to any particular curb or any particular ventilator, when the ventilator is to be utilized upon -buildings within which extraneous noise is objectionable, I prefer to utilize the curb disclosed in my copending application which as shown therein is substantially square in cross section and consists of side walls designated by the numeral 17, the lower side portion of each of which is inclined downwardly and outwardly to form a cant 18 which terminates in a base portion which is integral with and extends outwardly beyond a bottom wall 19 and is provided with spaced apertures through which screws 2t) may be inserted which as shown are threaded through roofing layers applied over a layer of insulation and into a threaded anchoring means 21 embedded in the insulation and roof of the building. To provide a support for my improved sound attenuating device, the upper portion of each side wall 17 extends inwardly and outwardly beyond the side` wall to form a top wall 22.

Acoustical insulation is provided in each side wall structure of the curb for attenuating miscellaneous sound waves originating outside of the building and power generated noises occurring within the ventilator. For retaining the insulation in place, each of the top walls 22 termi- 'riates in a downwardly extending flange 23 and'has a downwardly extending strip 24 spaced from each liange 23 and the bottom wall has upwardly extending strips 25 and 26 arranged in alignment with the respective downwardly extending flange 23 and the strip 24 and an upwardly extending strip 27 arranged in alignment with each side wall portion 17 to provide supports for slabs 28 and 29 arranged in each side wall which are Iformed of acoustical insulating material, such as felt or breglass. As sho'wn, each slab 28 is arranged between the downwardly extending flange 23 and strip 24 and the upwardly extending strips 25 and 26 of each side wall and each slab 29 is arranged between the downwardly extending strip 24 and the downwardly extending wall portion 17 and the upwardly extending strips 26 and 27 of each side wall. Acoustical insulating material designated by the numeral 30, such as breglass, may also be compressed and arranged in each of the triangularly-shaped cavities between the cant 18, bottom wall 19, and strip 27 of each side wall structure which'acoustical insulating .material may be inserted in place prior to the insertion of slabs 28 and 29. A perforated plate 31 which may be formed of aluminum is inserted between each of the slabs 28', flange 23, and strip 25 to protect slabs 28 from air passing through the curb and a layer of plastic material 31a, such as rubber, is arranged over the top wall 22 to fur-ther attenuate sound waves passing through the sound attenuating device andthe curb.

To hold the end portions of layers of roofing insulation surrounding the curb and to protect them from rain and other weather elements, and additional strip 32 integral with each side wall \17 and substantially parallel to ltheV cant 18, forms with the cant a recess to receive the free end portions of the roofing strips that extend upwardly along each ofthe cants.

The ventilator 3 is also of a well known type which is described more particularly in my copending application, Ser. No. 228,558, filed in the United States Patent O'ice on October 5, 1962, which has matured into Patent No. 3,202,080 and which consists of a base portion 33 which terminates in an upwardly extending venturi-shaped portion 34 to which a downwardly extending annular ange on a wall designated by the numeral 35 is secured by suitable means, such as rivets. Wall 35 rst extends radially outwardly and then upwardly in a substantially vertical direction relative to the base portion of the ventilator and terminates in an inverted U-shaped flange 36 through which a plurality of bolts extends, the head 37 of each of which bears against the bottom of the U-shaped flange 36 and extends upwardly through a plurality of annular tiers which are spacedfrom each other by tubes 38, 39 and 40, respectively. Each bolt is secured in place by a nut 41 arranged above the upper tier.

The lower tirer consists of an outwardly and downwardly inclined baftle 42 and a raised substantially liat central portion 43 which forms the upper wall of a fan compartment and supports a motor 44, the shaft of which is operatively secured to fan 45. As shown, the lower portion of the blades of the fan extend downwardly relative to the vertically extending portion of wall 35 which cuts o air from-the lower portion of the fan. Baffie 42 and the U- shaped flange 36 form an annular opening through which air may be forced outwardly through the ventilator which has substantially the same area as the duct means leading into the ventilator. The'central tier also consists of a 4- downwardly inclined baffle 46 and an upwardly extending annular central portion 47 which provides a space for the motor and the upper tier consists of a downwardly inclined baffle 48 and a raised central portion which forms a cover for the motor. When air is forced outwardly from the building between the baffle 42 and the U-shaped flange 36, a negative pressure is created above bathe 42 and the egress of air from the fan compartment draws hot air from the motor compartment which is replenished by cool air flowing into the motor compartment between baies 48 and 46.

To eliminate backdraft, the curbs are preferably provided with louvers 50 which may be opened and closed by a motor 51 as shown in FIGS. 1 and 2 or they may be moved to open position by the outward ow of air when the motor for operating the fan is energized and closed by gravity when the motor is deenergized. As shown in FIGS. 1 and 2 a frame 52 is provided which is supported on extensions on the oppositely disposed bottom walls and the louvers are pivotally mounted 4on rods journalled in the side walls of the frame. Each of the louvers is provided with upwardly inclined lugs 53 which lugs are secured to a bar 54 andare movable in unison to open and closed position by a motor 51 and a transmission means 55. The louvers shown in FIG. 6 are similar to those shown in FIGS. 1 and 2 but open automatically when the motor which drives the fan is energized and close by gravity when the motor is deenergized. The parts have accordingly been designated by the same reference numerals. As shown in FIG. 6, the frame is mounted on |cleats 56 secured to the bottom edge of the curb which in this modification is designated by the numeral 2a.

It will be noted that the outwardly extending flange of the inner wall of my improved device iits over the plastic material on the top wall 22 of the curb shown in FIGS. l and 2 of the drawing and its outer wall 4 engages a downwardly extending ange 57 ofthe top wall of the curb and the lower portion of the outer wall of my improved device is inclined outwardly to facilitate the application of the sound attenuating device to the curb. In the modification shown in FIG. 6, the bottom flanges of the inner walls of the sound attenuating device rest upon the upper portion of the curb and in both modilications a plastic material 58, such as rubber, is arranged over the inwardly extending ange 5 of the outer wall and: the outwardly extending ilange 9 of the inner wall to further attenuate sound waves passing through my device and the curb.

In my improved sound attenuating device, it will be noted that the outer walls 4 are spaced from the inner walls 7 and 8 and the inner walls 7 are irregular in shape, thus increasing their surface area. They are also perforated so that sound waves passing through the ldevice will contact the acoustical insulating material and will be attenuated. Sound waves are also attenuated by the acoustical insulation within perforated casing 15 or perforated casings 15 and 15a and While I do not desire to be limited to the size or frequency of the apertures in the inner side walls of the sound attenuating device and the casing or casings therein, they maybe approximately 1/16 of an inch in diameter and are preferably staggered relative to each other with the openings being arranged approximately -0/16 of an inch apart. Asthe sound waves pass downwardly through the curb, they are also attenuated by the acoustical material in the side walls of the curb and inthe triangularly-shaped portion formedr by the outwardly extending cant and to permit sound waves to penetrate into the acoustical material within the side walls of the curb, the openings in plate 31 are preferably of approximately the sameY size and are arranged in substantially the same manner as the openings in side walls 7 and 8. It will also be noted that the irregularly-shaped portion 12 of side walls 7 cause sound waves to be reiiected inwardly toward the tubular casing 15, or tubular casings 15 and 15a, to further attenuate the sound waves, and sound waves striking the lower portions of casing 15 or casings 15 and 15a, and the lower faces of the angularly shaped portions 13 of the side walls 7, are reflected downwardly into engagement with the side walls of the curb where they are further attenuated by the acoustical material therein.

What is claimed is:

1. A sound attenuating device including two pairs of oppositely disposed outer walls and two pairs of oppositely disposed inner walls, each of which inner walls is perforated and is arranged opposite to an outer wall, each of said outer walls having an inwardly extending upper flange and an outwardly inclined lower flange and each of the inner walls being perforated and having an outwardly extending upper flange secured to the upper flange extending inwardly from the outer wall opposite thereto and a lower flange secured to the outer wall opposite thereto at a spaced distance above its outwardly inclined lower flange, acoustical insulating material disposed between the inner and outer walls of said device and the inner walls of said device being shaped to define a passage for sound waves which are attenuated by the acoustical insulating material between the inner and outer walls.

2. A sound attenuating device including two pairs of oppositely disposed outer walls and two pairs of oppositely disposed inner walls which are shaped to provide a passageway for sound waves passing through the device, and each inner wall being perforated and spaced inwardly from an outer wall vand secured thereto at its upper and ylower portions to form two pairs of oppositely disposed casings, acoustical insulating material arranged in each casing, and an additional perforated casing extending between one pair of inner walls and secured thereto which also contains acoustical insulating material.

3. A sound attenuating device as definedin claim 2 in which the perforated casing extending between one pair of inner walls is arcuate in shape.

4. A sound attenuating device as defined in claim 2 in which the perforated casing extending between and secured to a pair of inner walls is substantially circular in shape and has a baffle therein to vary the density of acoustical insulating material therein.

5. A sound attenuating device including first and second pairs of outer walls with the walls in each pair being arranged in oppositely disposed relation to each other, a first pair of oppositely disposed inner walls having irregularly-shaped surfaces, one of which is arranged opposite to and spaced from one of the first pair of outer walls and the other of which is arranged oppositely to and in spaced relation to the other of the rst pair of outer walls, a second pair of oppositely disposed inner walls, one of which is arranged opposite to and in spaced relation to one of the second pair of outer walls and the other of which is arranged opposite to and in spaced relation to the other of the second pair of outer walls, a perforated casing arranged between and secured to the second pair of inner walls, each of said inner walls being perforated and said inner walls and casing defining passages for sound waves, and acoustical insulating material arranged between the inner and outer walls and in said casing for attenuating sound waves.

6. A sound attenuating device as defined in claim 5 in which a plurality of perforated casings having acoustical insulating material therein are arranged between and secured to the second pair of inner walls.

7. The combination of a curb having upwardly extending wall means and a substantially flat upper surface and a sound attenuating device, said sound attenuating device having two pairs of oppositely disposed outer walls and two pairs of oppositely disposed inner walls, each of which is disposed opposite to an outer wall, each of said outer walls having an inwardly extending upper flange, a portion extending below the upper edge of the curb and a lower flange inclined outwardly from the curb to facilitate the application of the sound attenuating device to the curb and each of the inner walls being perforated and having an outwardly extending upper flange secured to the inwardly extending flange on the outer wall opposite thereto and a lower flange secured to the outer wall opposite thereto at a spaced distance above its outwardly inclined lower flange, acoustical insulating material disposed b'etween the inner and outer walls of the sound attenuating device and the lower flange of each of the inner walls being shaped to fit upon the flat upper surface gf the curb.

8. The combination of a curb having upwardly extending side walls and a top wall having downwardly extending outer flanges and a sound attenuating device, said sound attenuating device having two pairs of oppositely disposed outer walls and two pairs of oppositely disposed inner walls, each of said outer walls having an inwardly extending upper flange, a portion extending below the upper edge of the curb which engages a flange on the top wall of the curb, and a lower flange inclined outwardly from the curb to facilitate assembly of the sound attenuating device on the curb and each of the inner walls being perforated and having an outwardly extending inner upper flange secured to the upper flange of the outer wall opposite thereto and a lower flange secured to the outer wall opposite thereto at a spaced distance above its outwardly inclined lower flange, acoustical insulating material disposed between the inner and outer walls of the sound insulating material and the lower flange of each of the inner walls being shaped to fit upon the upper substantially flat surface of the curb.

9. The combination of a curb, a sound attenuating device, and a ventilator, said curb consisting of upwardly extend walls having substantially flat upper surface and a layer of plastic material arranged over the flat surface of the curb, said sound attenuating device having two pairs of oppositely disposed outer walls and two pairs of oppositely disposed inner walls, each of which inner walls is arranged in opposed relation to an outer wall and each of said outer walls having an inwardly extending upper flange, a portion extending below the upper edge of the curb, and a lower flange inclined outwardly from the curb to facilitate assembly of the sound attenuating device on the curb, and each of the inner walls of the sound attenuating device being perforated and having an outwardly extending upper flange secured to the inwardly extending upper flange on the outer wall opposed thereto to provide an upper wall and a lower flange secured to the outer wall opposed thereto at a spaced distance above its outer inclined lower flange which rests upon the plastic material on the upper flat surface of the curb, acoustical insulating material -disposed between the inner and outer walls of said attenuating device, a second layer of plastic material resting upon each of the upper walls of the sound attenuating device, and said ventilator having a base portion resting upon the second layer of plastic material and having a downwardly extending flange arranged in opposed relation to the upper portion of each of the outer walls of the sound attenuating device.

10. The combination of a sound attenuating device and a curb, said curb having two pairs of oppositely disposed side walls, each having acoustical insulating material and each provided with a perforated facing material for permitting sound waves to contact the acoustical insulating material, a flat top wall for each of the side walls which terminates in a downwardly extending outer flange, said sound attenuating device including first and second pairs of outer walls with the walls of each pair disposed in opposed relation to each other, a first pair of oppositely disposed inner walls having irregularly-shaped surfaces, one `of which is arranged opposite to and spaced from one of the first pair of oppositely disposed outer walls and the other of which is arranged oppositely to and in spaced relation to the other of the first pair of outer walls, a second pair of oppositely disposed inner walls, one of which is arranged opposite to and in spaced relation to one of the second pair of outer walls and the other of which is arranged opposite to and in spaced relation to the other of the second pair of inner walls, each of said inner walls being perforated and having lower flanges secured to the outer'wall which engages the upper wall of said curb, each of the outer walls of said sound attenuating device having a lower portion which engages the downwardly extending ange on the curb and an outwardly inclined flange for facilitating assembly of theV sound attenuating device on the curb, and yeach of the inner walls of said sound attenuating device being perforated and acoustical insulating material arranged between its inner and outer walls for attenuating sound waves.

11. A sound attenuating device including two pairs of oppositely disposedwalls, acoustical insulating material arranged yadjacent each of said walls, each of said walls having an inwardly extending ange arranged above the acoustical insulating material adjacent thereto and an outwardly and downwardly inclined lower flange arranged fbelow the acoustical insulating material, and said walls and acoustical insulating material forming a passageway for sound waves.

l12. A sound insulating device as dened in claim 11 in which acoustical insulating material in tubular form is arranged between one of the pairs of oppositely disposed side walls.

13. A sound insulating device as defined in claim 11 in which a plurality of acoustical insulating tubes are arranged between one of the pairs of oppositely disposed side walls.

14. A sound attenuating device as defined in claim 11 in which the acoustical insulating material arranged adjacent each of one pair of oppositely disposed side walls is irregular in shape to increase the sound attenuating eiect Iof the acoustical insulation material through which the sound waves pass.

V15. A sound attenuating device as defined in claim y14 in which the acoustical insulating material in tubular form is disposed between the other pair of oppositely disposed side walls and in which sound waves striking the irregu- .larly sound attenuating insulating material adjacent ea'ch having two pairs of opposite disposed side walls, acoustical insulating material arranged adjacent each side wall of the attenuating device and each of the side walls of the attenuating device having an inwardly extending tiange -arranged above the acoustical insulating material adjacent thereto and a lower portion arranged below the acoustical insulating material adjacent thereto which lower portion of each side wall of the attenuating device engages one of the downwardly extending flanges on the top wall of the curb and in which each of the side walls of the attenuating device is provided with a downwardly and outwardly extending ange for facilitating the assembly of the attenuating device on the curb.

References Cited UNITED STATES PATENTS 1,865,677 7/1932 Cheyney. 2,551,004 5/1951 Johnson 98-43 2,745,509 5/ 1956 Argentieri 181-42 3,110,357 11/1963 Jenn et al. 181--679X 3,212,425 10/ 1965 Hazen et al. c 98-43 FOREIGN PATENTS 357,147 9/1931 Great Britain.

RICHARD B. WILKINSON, Primary Examiner. R. S. WARD, Assistant Examiner. 

11. A SOUND ATTENUATING DEVICE INCLUDING TWO PAIRS OF OPPOSITELY DISPOSED WALLS, ACOUSTICAL INSULATING MATERIAL ARRANGED ADJACENT EACH OF SAID WALLS, EACH OF SAID WALLS HAVING AN INWARDLY EXTENDING FLANGE ARRANGED ABOVE THE ACOUSTICAL INSULATING MATERIAL ADJACENT THERETO AND AN OUTWARDLY AND DOWNWARDLY INCLINED LOWER FLANGE ARRANGED BELOW THE ACOUSTICAL INSULATING MATERIAL, AND SAID WALLS AND ACOUSTICAL INSULATING MATERIAL FORMING A PASSAGEWAY FOR SOUND WAVES. 